Air bags installed in vehicles such as automobiles have a wide range of applications such as bags for protecting the head region, chest, waist, and knees of a passenger, curtain bags provided on the side window, and so on. However, the space inside a vehicle is limited, and hence it is often impossible to install a gas generator for each application. Therefore, it is important to reduce the size of the gas generator so that a bag for use in a variety of applications can be inflated effectively in a limited space.
Furthermore, in recent years larger air bags than those of the past are used in lateral collision applications, and a gas generator having a large output is necessary to inflate such an air bag within the required time period.
In response to these two demands, ideas such as increasing the size of a conventional gas generator without altering its basic constitution, or simply combining a plurality of conventional gas generators, have been considered. With these methods, however, the required space-saving cannot be achieved.
JP-A 11-139241 discloses arranging a plurality of gas generators in parallel inside the steering wheel. U.S. Pat. No. 5,658,010 discloses arranging two cylindrical inflators in parallel. JP-A No. 10-181517 discloses a module in which a filter is disposed on the exterior of a filterless inflator. JP-A 03-175298 discloses an inflator in which two combustion chambers and a filter chamber are provided independently of each other.